| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface potential detecting device capable of making a circuit simple, compact, and lightweight and reducing cost. SOLUTION: A switching circuit 2 selects and outputs signals S11-S41 and S12-S42 supplied from surface potential sensors 11-14 at different temporal timing for every one of the surface potential sensors 11-14. One signal processing circuit 3 is connected to the surface potential sensors 11-14 via the switching circuit 2. A first bias circuit 36 impresses a positive bias voltage to raise the level of a surface potential detection signal Z. A second bias circuit 39 impresses a negative bias voltage to offset the positive bias voltage impressed by the first bias circuit 36 on the basis of an analogue voltage signal supplied from a microcomputer 42 and D/A converting circuit 41. |
